Printed Soft Optical Waveguides of PLA Copolymers for Guiding Light into Tissue

Abstract

The application of optical technologies in treating pathologies and monitoring disease states requires the development of soft, minimal invasive and implantable devices to deliver light to tissues inside the body. Here, we present soft and degradable optical waveguides from poly­(d,l-lactide) and derived copolymers fabricated by extrusion printing in the desired dimensions and shapes. The obtained optical waveguides propagate VIS to NIR light in air and in tissue at penetration depths of tens of centimeters. Besides, the printed waveguides have elastomeric properties at body temperature and show softness and flexibility in the range relevant for implantable devices in soft organs. Printed waveguides were able to guide light across 8 cm tissue and activate photocleavage chemical reactions in a photoresponsive hydrogel (in vitro). The simplicity and flexibility of the fiber processing method and the optical and mechanical performance of the obtained waveguides exemplify how rational study of medically approved biomaterials can lead to useful inks for printing cost-effective and flexible optical components for potential use in medical contexts.

Optical characterization of 3D printed PLA and ABS filaments for diffuse optics applications

“…To further investigate the cause of the differences in the spectra shown in Fig 2, we performed also XRD measurements on the two samples (data can be found in 10.5281/zenodo.4736126). XRD characterization confirms the amorphous nature of these materials when 3D printed, as already reported by Feng et al [19]. This analysis also shows the presence of CaCO3 in the 3DiTALY sample, suggesting either that different fabrication processes have been used by the two producers, or the presence of some contamination.…”

“…The behaviour of its index of refraction was studied from 300 to 1300 nm, observing a reduction from 1.499 to 1.440 [ 18 ]. Also the optical absorbance of the raw PLA has been investigated in the range 350–800 nm, and it was found always <0.12, so that it is possible to affirm that PLA is a transparent material [ 19 ]. Feng et al .…”

“…The behaviour of its index of refraction was studied from 300 to 1300 nm, observing a reduction from 1.499 to 1.440 [18]. Also the optical absorbance of the raw PLA has been investigated in the range 350-800 nm, and it was found always <0.12, so that it is possible to affirm that PLA is a transparent material [19]. Feng et al measured 1 g of polymer powder and melted it in an oven at 130˚C under vacuum for 12 h. The crucial point is that the heated powder is a different sample than the PLA printed with a 3D printer.…”

Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain

“…They demonstrated the viability of their process for fibers with a diameter down to 200 µm. Lastly, it should be mentioned that a range of optical fibers and waveguides have recently been presented made from poly lactic acid (PLA) and its derivatives [ 144 , 145 , 146 , 147 ]. However, these fibers are not suited for long-term optogenetic therapies, due to the fast degradation time of the material, which is in the order of weeks to months [ 147 ].…”

Crosstalk Analysis and Performance Evaluation for Torus-Based Optical Networks-on-Chip Using WDM

“…In Equation ( 13), L b represents the insertion loss when the optical signal goes through a bending waveguide, L P/C_ON/OFF is the loss coefficient when the signal traverses a WPSE/WCSE at the ON/OFF state, and superscript k is the number of bending waveguides, WPSE/WCSE at the ON/OFF state, and waveguide crossings in the optical transmission link. In Equation (6), the transmission loss is denoted by L trans , in which α is the waveguide attenuation coefficient and L is the optical transmission length [36].…”